JPH0820067A - Production of saturated polyester resin sheet and molded product - Google Patents

Abstract

PURPOSE:To efficiently produce a stretched sheet excellent in heat resistance and shaping properties by extruding a saturated polyester resin in a molten state to form a sheet and preheating the sheet to a predetermined temp. range to stretch the same in one direction in a predetermined stretching magnification and immediately cooling the stretched sheet at a predetermined temp. CONSTITUTION:A saturated polyester resin sheet is produced by a method wherein a saturated polyester resin is extruded in a molten state to form a sheet which is, in turn, preheated to a temp. range of 90110 deg.C and the preheated sheet is stretched within a temp. range lower than the preheating temp. by 0.5-15 deg.C in one direction in stretching magnification of 2.0-4.0 times to be immediately quenched so as to become a temp. equal to or lower than T+10 deg.C and lower than stretching temp. by 20-70 deg.C. By applying this heat treatmet, a sheet supressed in the return of the orientation capable of keeping the uniformization of sheet thickness, good in moldability and shaping properties and having a proper degree of crystallization can be easily obtained within an extremely short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a saturated polyester resin sheet and a molded product thereof which can be advantageously molded into a molded product such as a hot-fillable container having excellent heat resistance.

[0002]

2. Description of the Related Art A-PET sheets and C-PET sheets have been heretofore known and widely used as saturated polyester resin sheets used for food containers.
However, when A-PET is used, the heat resistance is inferior. On the other hand, C-PET is excellent in heat resistance, but when it is molded using only a heating mold and immediately taken out, it has no rigidity and loses its shape. Had the problem of causing.

Therefore, as a saturated polyester resin sheet which is more excellent in heat resistance and moldability than ever before, for example, in JP-A-56-38216, the crystallinity is 25% or less and the plane orientation index is 0.02 to 0.02. A 0.12 biaxially stretched polyester sheet was pressure-molded and then heated in a specific temperature range.
A technique for obtaining a molded article by cooling and then removing it from a mold is described.

[0004]

However, JP-A-56-
The technique described in Japanese Patent No. 38216 has the inconvenience of requiring heating and cooling steps during molding, and
As described in the publication, when the crystallinity of the stretched sheet is set to a high value without heat treatment, the stretched sheet needs to be held at a stretching temperature for a considerably long time during stretching. The productivity was significantly reduced.

The problem to be solved by the present invention is that it is possible to efficiently produce a stretched sheet which is extremely excellent in heat resistance and moldability (mold reproducibility), and in the molding process there is no complicated process. It is an object of the present invention to provide a method for producing a stretched sheet, in which the molding cycle is shortened without the need for, and a molded product having good heat resistance and good moldability can be easily obtained, and a molded product.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems of the present inventor, when a saturated polyester resin is extruded and stretched to obtain a stretched sheet, preheating is performed under a specific temperature condition, and then a specific temperature It was found that a stretched sheet having excellent moldability and moldability can be easily obtained by carrying out stretching under the temperature conditions and stretching ratio, and then subjecting to rapid cooling or heat treatment in a specific temperature range to complete the present invention. Came to.

That is, in the present invention, a saturated polyester resin is melt extruded into a sheet (step 1), and then 9
It is preheated to a temperature range of 0 to 110 ° C. (step 2), and the draw ratio in one direction is 2.0 to 4.0 times in a temperature range of 0.5 to 15 ° C. lower than the preheating temperature. After uniaxial stretching or biaxial stretching within the range (step 3), immediately after Tg + 10 ° C. or lower, and 20 to 70 higher than the stretching temperature.
A method for producing a saturated polyester resin sheet, which comprises rapidly cooling so as to lower the temperature (step 4),

The saturated polyester resin is melt extruded into a sheet (step 1), preheated to a temperature range of 90 to 110 ° C. (step 2), and further heated to 0.
In the low temperature range of 5 to 15 ° C, the draw ratio in one direction is 1.2.
˜2.0 times uniaxial stretching treatment or biaxial stretching treatment (step 3 ′), and then heat treatment in a temperature range of 100 to 180 ° C. 4 ') and a molded product obtained by pressure forming the stretched sheet obtained by the manufacturing method.

In the production method of the present invention, "Tg"
Is the extrapolated glass transition start temperature in the DSC method described in JIS K 7121 when the temperature is raised at a heating rate of 10 ° C./min.

The saturated polyester resin used in the present invention is obtained by reacting phthalic acid or an ester-forming derivative thereof (hereinafter referred to as phthalic acid) and ethylene glycol as essential components. Examples of phthalic acids include isophthalic acid, orthophthalic acid, terephthalic acid, orthophthalic anhydride, dimethyl terephthalate and the like.
The reaction conditions between phthalic acids and ethylene glycol will be explained by taking the reaction between dimethyl terephthalate and ethylene glycol as an example. The transesterification reaction is carried out at 280 ° C to 300 ° C in the presence of a catalyst under reduced pressure as necessary. Generally, the reaction is terminated after confirming that a predetermined amount of methanol has been obtained. The saturated polyester resin may be one obtained by reacting phthalic acids with ethylene glycol as an essential component as described above, but other alcohols or carboxylic acids may be used in combination as necessary. Examples of other alcohols and carboxylic acids used at this time include alcohols such as 1,3-propylene glycol, 1,4-butanediol, and cyclohexanedimethanol,
Examples thereof include carboxylic acids such as adipic acid, sebacic acid, trimellitic acid, and pyromellitic acid. As the catalyst that can be used in the dehydration condensation reaction and the transesterification reaction, for example, a titanium compound such as tetraisopropyl titanate, a tin compound such as tin octylate, a zinc compound such as zinc acetate, an antimony compound, Examples include catalysts such as germanium compounds.

The saturated polyester resin used in the present invention has an intrinsic viscosity (IV value) of 0.5 to 1.2 dl / g in view of good melt extrusion processability and physical properties after heat treatment.
Can be used. The intrinsic viscosity is a value obtained by dissolving the polymer in a phenol / tetrachloroethane mixed solution having a weight ratio of 1: 1 and measuring the viscosity at 30 ° C. The intrinsic viscosity of this resin is preferably 0.7 to 0.9 dl / g in terms of impact resistance of the molding container. Normally, in a C-PET container, it is necessary to set the intrinsic viscosity as high as about 0.9 dl / g from the viewpoint of impact resistance, but when stretch orientation is applied as in the present invention, a comparison of 0.7 to 0.8 dl / g is made. Impact resistance can be maintained even if a resin having a relatively low intrinsic viscosity is used. When the precision of the moldability is not so required, the resin having 0.7 dl / g or less can be used by increasing the draw ratio.

In the production method of the present invention, the above-mentioned saturated polyester resin can be used to obtain a target stretched sheet by two methods.

That is, step 1 of the detailed saturated polyester resin is melt-extruded to form a sheet, step 2: then preheat to a temperature range of 90 to 110 ° C. step 3: further 0 than the preheating temperature. After performing uniaxial stretching or biaxial stretching in a temperature range of 0.5 to 15 ° C. lower in one direction and a stretching ratio of 2.0 to 4.0, step 4: immediately after Tg + 10 ° C., and A method of quenching so as to be 20 to 70 ° C. lower than the stretching temperature (hereinafter,
Abbreviated as "method 1"), or step 1: melt extrusion into a sheet, step 2: preheat to a temperature range of 90 to 110 ° C, step 3 ': further 0.5 than preheating temperature. After a uniaxial stretching treatment or a biaxial stretching treatment with a unidirectional stretching ratio of 1.2 to 2.0 times in a lower temperature range of -15 ° C, step 4 ': heating in the temperature range of 100 to 180 ° C. It is a method of processing (hereinafter, abbreviated as “method 2”).

Step 1 is a step of melt-extruding a saturated polyester resin to obtain a sheet-shaped long raw material, and the method is not particularly limited, but it can be performed, for example, as follows.

That is, a preferred method is one in which the saturated polyester resin is adjusted to have a water content of 50 PPM or less by a dryer or a twin-screw extruder with a vent, melted and weighed by an extruder, and extruded from a die having an adjusted lip interval. To be

If necessary, the saturated polyester resin may include other synthetic resins, lubricants, antiblocking agents, antioxidants, antifogging agents, antifog agents, plasticizers, antistatic agents, flame retardants, colorants, etc. You may add the additive of.

The synthetic resin which can be used in this case is a known and commonly used synthetic resin, for example, a co-condensed polyester resin obtained by co-condensing phthalic acid and ethylene glycol with another reactive component, polyethylene adipate, Polybutylene terephthalate and the like, as the lubricant, for example, titanium oxide, fine particle silica, activated clay and the like, as the anti-fogging agent, for example, sorbitan fatty acid ester, glycerin fatty acid ester, etc., as the anti-fog agent, for example perfluoro Alkyl group-containing carboxylic acid, perfluoroalkyl group-containing carboxylic acid sorbitan ester, perfluoroalkyl group-containing carboxylic acid glycerin ester and the like, and plasticizers include, for example, dioctyl phthalate, epoxidized soybean oil, aliphatic polyesters and the like. .

Further, at the time of sheet production, it is possible to extrude melted saturated polyester resin from a plurality of extruders to form a multilayer structure. For example, if an attempt is made to obtain a three-layered saturated polyester-based resin multilayer sheet, a recovered product for the central layer or an inexpensive saturated polyester-based resin obtained by carrying out a reaction using an antimony catalyst or the above-mentioned third
It is possible to use a saturated polyester resin in which components are co-condensed, or a mixture thereof, and use a virgin polyester resin for both outer layers.

Various functionalities can be imparted to the surface by adding the above-mentioned additives to the saturated polyester resin forming both outer layers. At this time, it is a matter of course that these additives may be coated on the surface after obtaining the multi-layered sheet. A surface treatment such as metal deposition or corona discharge treatment can be applied on the saturated polyester resin sheet material, or a heat seal layer such as a saturated polyester elastomer, ethylene-vinyl acetate resin or polyurethane resin can be provided. Is also possible.

The melting temperature at which the saturated polyester resin is melt-kneaded in the extruder is not particularly limited, but is not less than the melting point of the saturated polyester resin, specifically 260 to 34.
It is preferably 0 ° C.

The sheet-like material melt-extruded at the above temperature is usually cast to have a predetermined thickness,
Cooled if necessary. At that time, depending on the thickness of the sheet, if the thickness is thick, a touch roll and an air knife are used, and if the thickness is thin, electrostatic pinning is properly used to form a uniform sheet. The distance between the lips of the dies during melt extrusion is usually 0.2 to 3.0 mm, but it is preferably 0.2 to 1.0 mm from the viewpoint of good film formability.

Next, in step 2, the sheet obtained in step 1 is preheated in the temperature range of 90 to 110 ° C. Here, the sheet may be once cooled to room temperature in step 1 and then heated to the temperature range, or
The step of cooling from the step 1 to the temperature range of interest may be referred to as step 2, and may be directly applied to the next step, step 3 or step 3 ′.

The method of preheating is not particularly limited, but for example, in the preheating zone where the heater is provided, the sheet material obtained in step 1 is continuously introduced into the tenter. The method of heating with.

When sequential biaxial stretching, which will be described in detail later, is carried out, longitudinal stretching may be carried out by means of rolls before introducing the original sheet into the tenter.

Then, in step 3 or step 3 ', the film is stretched. In the production method of the present invention, uniaxial stretching or biaxial stretching may be used. Here, the uniaxial stretching includes longitudinal uniaxial stretching and lateral uniaxial stretching, which may be either in the present invention, but in terms of moldability and moldability, further workability in step 3 or step 3 '. From the above point, it is preferable to perform transverse uniaxial stretching.

The method for carrying out the lateral uniaxial stretching is not particularly limited, but for example, the sheet raw fabric obtained through the step 1 is introduced into a tenter and preliminarily placed in a preheating zone provided with a heater. It is heated (step 2) and subsequently introduced into a stretching zone maintained at a temperature range 0.5 to 15 ° C. lower than the preheating temperature. In this stretching zone, the sheet is stretched to a desired ratio in the direction (transverse direction) perpendicular to the sheet advancing direction.

In the drawing zone, the sheet is gradually cooled from the preheating temperature to a temperature lower by 0.5 to 15 ° C. than the preheating temperature. At this time, the average slow cooling rate is 10 to 30.
C./min. Is preferred. Examples of the method of calculating the slow cooling rate include a method of calculating by the following formula.

(Preheating zone temperature-drawing zone temperature) / passing time of the drawing zone

The draw ratio depends on Method 1 or Method 2, and is 2.0 to 4.0 times in Method 1 and 1.2 to 2.0 times in Method 2.

Next, as the biaxial stretching method, there are a simultaneous biaxial stretching method and a sequential biaxial stretching method, and the sequential biaxial stretching method is preferable because it is advantageous for production. In the longitudinal stretching of the sequential biaxial stretching method, stretching can be performed by providing a peripheral speed difference between roll speeds of a plurality of rolls, and usually, in a film, a method of shortening a free path of adjacent small diameter rolls is used. In this case, since the film thickness is large and scratches are likely to occur, it is preferable to provide a peripheral speed difference between the two rolls and to provide an infrared heating device on the sheet surface between the rolls to adjust the longitudinal stretching ratio and the like.

The stretching ratio in the machine direction is not particularly limited, but it is preferably 2.0 times or less from the viewpoint of facilitating thickness adjustment during transverse stretching.

The stretching temperature for the longitudinal stretching is not particularly limited, and in any of Method 1 and Method 2, it is usually 75 to 1.
Although the temperature is 10 ° C., it is preferable that the film is preheated to 90 to 110 ° C. with a heating roll and then stretched in a temperature range lower by 0.5 to 15 ° C. than the preheating temperature.

After the longitudinal stretching is performed in this way, preliminary heating is performed in step 2, and then stretching is performed in the direction perpendicular to the sheet advancing direction (transverse direction) in step 3 or step 3 '.

Specifically, for example, a longitudinally stretched sheet is introduced into a tenter, preheated in a preheating zone provided with a heater (step 2), and then 0.5 to 15 ° C. higher than the preheating temperature. It is introduced into a stretching zone maintained in a low temperature range and is stretched in the stretching zone in a direction (transverse direction) perpendicular to the sheet advancing direction to a desired ratio.

As described above, the temperature of the stretching zone is in the range of 0.5 to 15 ° C. lower than the preheating temperature, but above all, from the viewpoints of the appearance of the sheet, the degree of orientation, and the like. It is preferable that the temperature range is 75 to 100 ° C.

The sheet is gradually cooled in the tenter from the preheating temperature to a temperature lower by 0.5 to 15 ° C. than the preheating temperature. At this time, the average slow cooling rate is 10 to 30 ° C.
/ Min is preferable. This slow cooling rate can be calculated in the same manner as in the case of the above uniaxial stretching.

The draw ratio for transverse stretching is not particularly limited, and can be appropriately set according to the draw ratio of each of Method 1 and Method 2. That is, in Method 1, the draw ratio in one direction is in the range of 2.0 to 4.0 times.
When the stretching ratio in the machine direction is less than 2.0 times, the stretching ratio in transverse stretching is set to 2.0 to 4.0 times.

On the other hand, in the method 2, when the stretching ratio in the longitudinal direction is 1.2 to 2.0 times, the transverse direction can be arbitrarily set to 2.0 times or less, and the stretching ratio in the longitudinal direction is 1. If it is less than twice, the horizontal direction is set to 1.2 to 2.0 times.

The sheet stretched through the above steps is quenched in Method 1 (Step 4) and heat-treated in Method 2 (Step 4 '). That is, in Method 1, after performing uniaxial stretching or biaxial stretching within a temperature range of 0.5 to 15 ° C. lower than the preheating temperature and a draw ratio in one direction of 2.0 to 4.0 times. Then, in step 4, it is immediately cooled to Tg + 10 ° C. or lower and 20 to 70 ° C. lower than the stretching temperature.

The method of quenching is not particularly limited, and examples thereof include a method of introducing the stretched sheet coming out of the stretching zone in a tenter into a heat setting zone set to a predetermined temperature. By such rapid cooling after stretching, it becomes possible to suppress the return of the sheet orientation and maintain the uniform sheet thickness, and further, the moldability becomes extremely excellent.

Further, in the method 2, the temperature is higher than the preheating temperature by 0.
In the low temperature range of 5 to 15 ° C, the draw ratio in one direction is 1.2.
After the uniaxial stretching treatment or the biaxial stretching treatment of 2.0 times, a heat treatment is performed in a temperature range of 100 to 180 ° C. as a step 4 ′.

The heat treatment method is not particularly limited, but it is 100 to 180 ° C. in the heat setting zone.
The method of selectively adopting the temperature of and heating for a short time of 5 to 60 seconds, more preferably 5 to 30 seconds to crystallize.

By carrying out such a heat treatment, it is possible to suppress the reversion of the orientation and maintain the uniformity of the sheet thickness, and also the sheet having an appropriate crystallinity with good moldability and moldability. Can be easily obtained in an extremely short time.

As described above, it is a particularly important technique in the present invention to use the cooling treatment or the heat treatment in the heat setting zone as the final means for adjusting the sheet elasticity and the uniformization of the sheet thickness, and this means is used. This makes it possible to finally obtain a sheet that achieves both moldability and uniform thickness in a short time, and further, the productivity of the heat-resistant container becomes extremely excellent.

The physical properties of the saturated polyester resin sheet thus obtained are not particularly limited, but the thickness is 50 to 1000 μm, more preferably 150.
It is preferable that it is from ~ 700 μm in terms of molding stability during thermoforming, or difficulty in drawdown by a cooling roll immediately after film formation, and in terms of excellent moldability and strength when formed into a molded product. Return stress is 4 in terms of thickness
0 kg / cm ² or less, and more preferably is preferably 20 Kg / cm ² or less, in particular of the transverse uniaxial stretching in the step 2 - in the case of bets is preferably particularly 10 Kg / cm ² or less.

Orientation return stress means ASTMD-150.
Measured in accordance with 4 above, it is the force that the sheet material shows when it is heated to obtain the sheet material for stretching, and the maximum stress Is divided by the cross-sectional area of the sheet, and is an index showing the degree of molecular orientation of the stretched sheet-shaped material.

Further, in the above method 1 and method 2,
When the longitudinal uniaxial stretching and the transverse uniaxial stretching are performed, the releasability from the mold and the moldability can be remarkably improved by adjusting the storage elastic modulus of the finally obtained sheet.

That is, the uniaxially stretched sheet obtained through steps 1 to 4 or steps 1 to 4'is a dynamic viscoelasticity measuring device (JIS-K-7198, method A, heating rate 3 ° C).
/ Min), the minimum value of the storage elastic modulus of the saturated polyester resin sheet in the range of 0 to 200 ° C. is 0.65 × 10 ^{8 to} 7.
It is preferably 0 × 10 ⁸ dyn / cm ² , and in the case of Method 2, 4.0 × 10 ^{8 to} 15.0 × 1.
It is preferably 0 ⁸ dyn / cm ² .

Next, a method for producing the molded article of the present invention using the saturated polyester resin sheet thus obtained will be described.

A molded product having a predetermined shape can be obtained by pressure molding the above saturated polyester resin sheet using a heating mold.

The pressure forming used in the present invention may be either pressure forming or vacuum pressure forming. The molding conditions are not particularly limited, but the conditions for molding using a sheet, a heating mold and a hot plate pressure air molding machine are: hot plate temperature 9
0 to 120 ° C., heating time by hot plate 0.5 to 6 seconds, more preferably 1 to 3 seconds, mold temperature 120 to 180 ° C., more preferably 130 to 160 ° C., heat molding time 1 to 20 by mold Second, more preferably 1 to 10 seconds, molding pressure 1 to
10kg / cm ^2, more preferably from 3~5kg / cm ^2.

In this case, an excellent molded product can be obtained without causing mold reproducibility and rain drop due to insufficient heating.

The molded product thus obtained has incineration resistance, oil resistance, chemical resistance, safety and hygiene properties, tasteless and odorless, printability, and aroma retention, and at the same time, has outstanding heat resistance. Indicates.

These molded articles are widely used for food and general packaging such as pudding, jam, mousse, instant curry and other hot fill containers, as well as clear cases, press-through pack packaging, carrier tapes and window coverings.

Next, the present invention will be specifically described with reference to examples.

[0056]

【Example】

Example 1 Intrinsic viscosity (IV value) obtained by condensing phthalic acid and ethylene glycol 0.75 dl / g, crystallinity 5%
Using unmodified PET raw material of less than 2 parts, water is removed by a two-stage vent in a twin-screw extruder, resin temperature is 290 ° C., lip interval is 90
Casting cooling temperature 50 to 6 using 0 μm die
T-die extrusion sheeting with a touch roll was performed at 0 ° C, and the transparency and surface state thickness distribution were good, and the crystallinity was 5
%, A raw sheet having a sheet thickness of 640 μm was produced.

Next, the obtained raw sheet was used together with an infrared heating device and stretched at a stretching temperature of 90 ° C. in the longitudinal direction by a factor of 1.5 to obtain a 350 μm slightly stretched longitudinally stretched sheet. The orientation return stress in this case was 20 kg / cm ² . In order to further carry out the transverse stretching treatment of this longitudinally stretched sheet, it is introduced into a tenter, and the preheating zone temperature is 98 ° C., the stretching zone temperature is 88 ° C., the heat setting zone temperature is 60 ° C., and
3 preheating zones, 3 drawing zones and 3 heat setting zones
It was drawn in 2.2 times so that it would pass in 0 seconds, and the thickness was 20
A 0 μm sheet was obtained. The orientation return stress of this sheet is M
D / TD = 15/26 kg / cm ² , the haze of the sheet was 1.0, and the standard deviation of the thickness was σ = 5 μm.

Next, this sheet-like material has a container opening of length × width = 15 cm × 6 cm, a drawing ratio of 0.3, and a curvature area of 4 at the bottom.
mm container specification heating mold, heating mold temperature 160
℃, heating time 2 seconds, hot plate temperature 110 ℃, heating pressure 1kg
/ Cm ² , molding time 5 seconds, molding pressure 3 kg / cm ² ,
Hot plate pressure molding was performed. All of these molded products had good mold reproducibility and surface condition. Further, the haze value of the molded product is 2.6, and the transparency is good. The heat resistance of a molded product after being left for 10 minutes when deformed by 2% is 130 ° C.
There was no change at 00 ° C.

Example 2 In the same manner as in Example 1, an original sheet having a thickness of 640 μm was obtained, and a neck-in sheet was formed at a length of 1.5 times. The preheating zone temperature was 94 ° C., the stretching zone temperature was 84 ° C. 1.8 times stretching, heat setting zone temperature 60 ℃, and preheating zone,
The OS value MD / TD = 20/33 and the thickness 20 were set such that the stretching zone and the heat setting zone were each passed in 30 seconds.
A 0 μm sheet was prepared.

Then, a molded container was prepared under the same conditions as in Example 1.

Example 3 An original sheet having a thickness of 640 μm was obtained in the same manner as in Example 1,
The sheet was necked in at a length of 1.8 times, a preheating zone temperature of 112 ° C., a stretching zone temperature of 102 ° C., a lateral stretching of 1.8 times, a heat setting zone temperature of 140 ° C., a preheating zone, a stretching zone, and a heat setting. The crystallinity is 9.2% and the OS value is MD / T by passing through each zone in 30 seconds.
A sheet having D = 0/0 kg / cm ² and a thickness of 200 μm was obtained.

Then, a molded container was prepared under the same conditions as in Example 1.

Example 4 Using an unmodified PET raw material having an intrinsic viscosity (IV value) of 0.97 dl / g and a crystallinity of less than 5%, the heat setting zone temperature was changed to 160 ° C. in the same formulation as in Example 3. , Crystallinity 15
%, OS value MD / TD = 0/0 Kg / cm ² , thickness 200 μm
Got a sheet of. Then, a molded container was produced under the same conditions as in Example 1.

Example 5 A sheet material having a thickness of 400 μm was obtained in the same manner as in Example 1,
It is introduced into the tenter without longitudinal stretching and the preheating zone temperature is 98.
C., stretching zone temperature 88.degree. C., transverse stretching 2.0 times, heat setting zone temperature 60.degree. C., preheating zone, stretching zone,
OS value MD / TD = 3/26 Kg / cm ² , thickness 200 μm as it passes through each heat setting zone in 30 seconds
Got a sheet of.

Then, a molded container was prepared under the same conditions as in Example 1.

Example 6 In the same manner as in Example 1, an original sheet having a thickness of 400 μm was obtained,
It is introduced into the tenter without longitudinal stretching and the preheating zone temperature is 98.
C., stretching zone temperature 88.degree. C., transverse stretching 2.0 times, heat setting zone temperature 60.degree. C., preheating zone, stretching zone,
OS value MD / TD = 10/34 Kg / cm ² , thickness 200μ, so that each heat setting zone passes in 30 seconds.
m sheets were obtained.

Then, a molded container was prepared under the same conditions as in Example 1.

Example 7 A sheet material having a thickness of 400 μm was obtained in the same manner as in Example 1,
It is introduced into the tenter without longitudinal stretching and the preheating zone temperature is 10
OS value MD / TD at 0 ° C., stretching zone temperature of 90 ° C., transverse 2.0 times stretching, heat setting zone temperature of 110 ° C., and passing through the preheating zone, stretching zone and heat setting zone in 30 seconds each. = 0/0 Kg / cm ² , thickness 200μ
m sheets were obtained.

Then, a molded container was prepared under the same conditions as in Example 1.

Example 8 A sheet material having a thickness of 400 μm was obtained in the same manner as in Example 1,
It is introduced into the tenter without longitudinal stretching and the preheating zone temperature is 10
The OS value MD is 0 ° C., the drawing zone temperature is 90 ° C., the transverse stretching is 2.0 times, the heat setting zone temperature is 130 ° C., and the preheating zone, the drawing zone, and the heat setting zone are each passed in 30 seconds. / TD = 0/0 Kg / cm ² , thickness 2
A sheet of 00 μm was obtained.

Then, a molded container was produced under the same conditions as in Example 1.

Comparative Example 1 A raw sheet having a thickness of 520 μm was obtained in the same manner as in Example 1,
A simultaneous biaxially stretched sheet having a longitudinal and lateral magnification of 2.0 × 2.0 at a stretching temperature of 90 ° C., the preheating zone temperature and the stretching zone temperature are both 90 ° C., and the passage time of the preheating zone and the stretching zone is set to 90 ° C. Each was set to 30 seconds to obtain a stretched sheet. Then, this was cut into 20 × 20 cm, fixed on a metal frame, and dried in a hot-air circulation type dryer until the crystallinity reached 9.0%. At this time, the drying time until the crystallinity reached 9.0% was 10 minutes.

Then, a molded container was produced under the same conditions as in Example 1.

Comparative Example 2 A raw sheet having a thickness of 520 μm was obtained in the same manner as in Example 1,
Simultaneously biaxially stretched at a stretching temperature of 90 ° C. with a longitudinal / horizontal ratio of 2.0 × 2.0, a preheating zone temperature and a stretching zone temperature of 90 ° C., and a heat setting zone temperature of 2
The temperature is set to 00 ° C., and the preheating zone, the stretching zone, and the heat setting zone are passed in 30 seconds, and the thickness is 130 μm
Got a sheet of.

Then, a molded container was produced under the same conditions as in Example 1.

Hereinafter, Examples 1 to 8 and Comparative Example 1 will be described.
The production conditions and property values of the sheet in Nos. 2 and 3, and Table 2 show the evaluation results of the sheet and the molded product. The methods for measuring physical properties in Table 1 and the methods for evaluation in Table 2 are as follows.

[Crystallinity] The density was measured in accordance with JIS-K-7112 and determined by the following formula. chi _c: Crystallinity (%) d: density of sample _{^{(g / cm 3) d c}} : density of perfect crystal ^{PET (g / cm 3) =} 1.4
55 d _a: density of completely amorphous ^{PET (g / cm 3) =} 1.3
35

[Minimum value E'by dynamic viscoelasticity measurement] JI
SK-7198, Method A, 0 at heating rate 3 ° C / min
The lowest value of the storage elastic modulus when measured in the temperature range of up to 200 ° C.

[Evaluation Method of Releasability] ◯: Can be easily taken out from the pressure molding machine. X: Mold release is poor and the molded product cannot be delivered from the pressure molding machine.

[Evaluation method of moldability] The bottom of the molded product is judged with an R gauge ◯: The radius of curvature is 4.0 mm.

X: A radius of curvature of 4.5 mm or more.

[Haze] JIS-K-7105, a value expressed as a ratio of diffuse transmittance to total light transmittance using an integrating sphere type light transmittance measuring device.

[Heat resistance] The molded product was placed in an oven at a predetermined temperature and left for 10 minutes in a container opening (before standing, vertical x horizontal = 15).
(cm × 6 cm) vertical and horizontal lengths were measured, and the temperature at the time of 2% contraction was examined from the rate of change.

[Impact resistance] Resin pellets 100 are applied to molded products.
g and put a sheet of 12 μm together with an adhesive to seal it, and with the bottom of the molded product facing downwards, drop one by one onto the concrete surface from a height of 5 m, and the 10 out of 10 molded products will be cracked. It was judged by the number of pieces.

[0085]

[Table 1]

[0086]

[Table 2]

[0087]

EFFECTS OF THE INVENTION According to the present invention, it is possible to efficiently produce a stretched sheet having excellent heat resistance and moldability (mold reproducibility), and a complicated process is required in the molding process. Without shortening the molding cycle,
It is possible to provide a method for producing a stretched sheet that can easily obtain a molded product having good heat resistance and moldability, and a molded product.

Claims (8)

[Claims] 1. A saturated polyester resin is melt-extruded to form a sheet (step 1), and then preheated to a temperature range of 90 to 110 ° C. (step 2), and the temperature is 0.5 to more than the preheating temperature. In the temperature range lower by 15 ° C., after stretching is performed in the range where the stretching ratio in one direction is 2.0 to 4.0 times (step 3), immediately after Tg + 10 ° C. or lower and 20 to 70 ° C. higher than the stretching temperature. A method for producing a saturated polyester resin sheet, which comprises rapidly cooling so as to lower the temperature (step 4). 2. A saturated polyester resin is melt extruded into a sheet (step 1), preheated to a temperature range of 90 to 110 ° C. (step 2), and further 0.5 to 15 ° C. higher than the preheating temperature. After stretching in a low temperature range with a draw ratio of 1.2 to 2.0 in one direction (step 3 ′), 10
A method for producing a saturated polyester resin sheet, which comprises performing heat treatment in a temperature range of 0 to 180 ° C. (step 4 ′). 3. The sheet finally obtained has a thickness of 50 to 50.
The manufacturing method according to claim 1, which has a thickness of 1000 μm. 4. The orientation return stress of the sheet finally obtained
But 40 Kg / cm ²The manufacturing method according to claim 3, wherein:
Law. 5. The saturated polyester resin has an intrinsic viscosity of 0.
It is 50-1.2 dl / g, The manufacturing method as described in any one of Claims 1-4. 6. The stretching step 3 is uniaxial stretching, and
The sheet finally obtained is a dynamic viscoelasticity measuring device (JI
SK-7198, Method A, heating rate 3 ° C / min)
The minimum value of the storage elastic modulus of the saturated polyester resin sheet in the range of 0 to 200 ° C. is 0.65 × 10
It is in the range of ^{8 to} 7.0 × 10 ⁸ dyn / cm ^2.
5. The manufacturing method according to any one of 5 to 5. 7. The stretching step 3 is biaxial stretching, and
The sheet finally obtained is a dynamic viscoelasticity measuring device (JI
SK-7198, Method A, heating rate 3 ° C / min)
The minimum value of the storage elastic modulus of the saturated polyester resin sheet in the range of 0 to 200 ° C. is 0.65 × 10
It is in the range of ^{8 to} 7.0 × 10 ⁸ dyn / cm ^2.
5. The manufacturing method according to any one of 5 to 5. 8. A molded product obtained by pressure forming a sheet obtained by the manufacturing method according to any one of claims 1 to 7.